Process for removing metallic contaminants from oils



Feb. 14, 1961 H. BlEBr-:R ETAL 2,971,905

PROCESS Foa REuovINC METALLIC CONTAMINANTS FROM oTLs Filed July 31, 1957 .v :mss mN 22% m5 22.1.25. 2 A. 22.22.2528 @N |v 9.35m... ,l5 .N 05o... 29;.. /mN m22 H/U? zoimw ww NN T Om Il m- Qmzanzov ON @z wuwwo lv e. N. 2o T 8 A. T @2.22.25 m. C 1 .1 mzoN n. f \@2.E2. Il Al A Il m w O D $5.05 r mmemm. x.. 1 2.. 4 2252? UH/H x1 m Herman Bieber Wolter M. Busch Inventors Louis Douber ...o .l H55 By WJJ-'WQAHorney United States Patent O PROCESS FOR REMOVING METALLIC CONTAM- INANTS FROM OILS HermanBleber,Rahwny,WaIterM.Baseh,Rmnso-,and Louis Danber, Cranford, NJ., non to ho Remh and Engineering Company, a corporation of ware l Filed July 31, 1,57, Sel'. No. 75,431

11 Claims. (Cl. 208-252) 1operations such as -catalytic cracking, hydroning and the like, the presence of very small concentrations of these contaminants in the feed stream leads to the rapid poisoning of the catalyst, causinga significant decrease in the product yield, an increase in coke and gas production, and a marked shortening in the life of the catalyst. In residual type fuels, such contaminants attack'the refractories used to line boilers and combustion chambers; cause slagging and the build up of deposits upon boiler tubes, combustion chamber walls and the blades of gas turbines; and severely comode high temperature metallic surfaces with which they come into contact.

Although there have been numerous methods proposed in the past for removing these contaminants from high boiling petroleum fractions, it has been found that such methods are largely ineffective, generallyresult in`A the loss of substantial quantities of the oil, and in most cases are prohibitively expensive. `As a result, it has generally been necessary to restrict the feed streams to catalytic petroleum processing units to those fractions which boil below the range in which the contaminants are found and to avoid as much as possible the use in fuels of fractions which contain the contaminants in high concentrations.

'I'he present invention provides a new and improved process for the removal of iron, nickel, vanadium and other metallic contaminants of the porphyrin type from high boiling petroleum gas oils and residua. In accordance with the invention, such contaminants are removed by treating the contaminated oil with a gaseous hydrogen halide and thereafter passing it to a settling, filtering or centrifuging operation where the oil and contaminants are separated. It has been discovered that the hydrogen halides coagulate the contaminants in a ilterable form and permit their ready removal without the formation of an acid sludge due to chemical reactions involving other constitutents of fthe oil. The process is thus a selective Patented Feb. 14, 1961 ice usually complex organic chelate compounds of the pob.

phyrin type. Two forms of the contaminants have been observed, one volatile at temperatures between about .1050 and 1250 F. and the other substantially non- 5 volatile at such'temperatures.

Because of entrainment during fractionation, both forms may be present in distillate fractions boiling as low as 950' F. or in some cases .even lower. It is believed that the volatile contaminants electrical charges. 'Ihe hydrogen halides apparently modify the solvating films about the colloidal metals and then, because there is inherently a small amount of moisture present, act as electrolytes to effect the coagulation of the contaminants. Regardless of the exact mechanism, howe/ver, it is apparent that the phenomenon is not merely a sludging due to chemical reaction between the halidesand the oil. This is clearly shown by the fact that, due allowance being made for the dierence in viscosity of the oil, the metallic contaminants are coagulated as readily at 30 F. as they are at 200 F.,

'Ihe concentration of metallic contaminants and the ratio of volatile to nonvolatile contaminants in crude oils vary considerably. The metals content of any distillate fraction will therefore depend upon the type and concentration of contaminants in 'the crude oil from which the fraction was distilled, the boiling range of the fraction, and the amount of entrainment which took place during the distillation. Heavy gas oil distilled from typical etudes may contain from about l to about 20 pounds of metallic contaminants per 1000 barrels. Residual fractions and gas oils derived from crudes which are particularly high in contaminants may contain as much as 200 pounds of metal per 1000 barrels. Similarly, in some fractions these contaminants may be predominantly of the volatile type and in others they may be essentially of the nonvolatile type, depending upon the crude source and the conditions under which the fraction was ob- Since both distillate and residual fractions may contain volatile as well as nonvolatile contaminants, a preliminary treatment for the conversion of the volatile compounds into coagulable, nonvolatile contaminants may be employed in conjunction with the hydrogen halide treatment in order to elect substantially complete metals removal. Such conversion may be readily accomplished one in which the yield of decontaminated oil is, quite by heat soaking the fraction at elevated temperatures or by a mild hydrotreating step. Following such a prev liminary treatment, substantially all of the metals in the oil exist in the nonvolatile form and may be readily coagulated by treatment with the gaseous hydrogen halide. Such a preliminary treatment is, of course, unnecessary in the case of very high boiling residual fractions and other oils which essentially contain only nonvolatile contaminants.

Treatment with gaseous hydrogen halides in accordance with the invention is most effective for the coagulation of nonvolatile contaminants from nonasphaltic fractions. The asphaltenes present in highly asphal'tic oils exert a solutizing eect upon the contaminants and tend to prevent their coagulation. The process of the invention may therefore also be employed in conjunction with a deasphalting step when asphaltic oils are to be treated. A particularly preferred method of combining i missible.

the two operations is tov inject thidiy'drogen halide into the dea'sphalting tower along with the solvent during deasphalting. The oil may also be deasphalted and thens recombined with thc asphalt prior to treatment for the removal of metals. /l It has been found that the deasphalting step in some way irreversibly destroys the solutizing etect of the asphaltenes 'and permits retention of the asphalt, thereby avoiding the high yield losses which would otherwise be incurred.

The treating temperature, the volume of hydrogen halide employed and the pressure at which the treatment is carried out may be varied considerably. It is preferred to treat at temperatures between about 30 and about 300 F; although higher temperatures may be employed, and at pressures ranging from about atmospheric up to about 150 p.s.i.g., higher pressures also being per- The reaction time may be varied from a few minutes to as much as 100 hours, depending upon the` temperature and pressure conditions selected. Excellent results have been obtained, for example, by treating at 250 F. and 80 p.s.i.g. for a period of about 4 hours.

The exact nature and objects of the invention can be more fully understood from the following description and the attached drawing which illustrates a preferred embodiment of the invention.

Referring now to the drawing, reference numeral 1 designates a crude oil distillationfzone which may constitute, for example, an atmospheric pipe still or a combination of atmospheric and vacuum distillation towers. Crude oil may be introduced into distillation zone l through line'2 and separated into a variety of fractions of dierent boiling ranges. Light hydrocarbon gases in the C, to C; range, such as methane, ethane, ethylene, propane and the like, may be taken on through an overhead line 3. Naphtha may be withdrawn from the distillation zone through an upper side stream withdrawal line such as line 4 and middle distillates such as kerosene and light gas oil may be taken on through lower lines auch as line 5. These middle distillate fractions may boil up to about 900 F. and will be substantially free of metallic contaminants. A heavy gas oil fraction boiling in the range between about 950 F. and about 1300V F. is withdrawn from the lower portion of the distillation zone through line 6. The residual fraction boiling above the heavy gas oil is taken off a bottoms product through line 7. Both of these two latter streams will contain substantial quantities of metallic contaminants. lt is preferred that the Acut point between the heavy gas oil and the residual fraction be selected so that essentiallv all of the volatile contaminants are carried into the heavy gas oil fraction and the residual fraction thus contains only nonvolatile contaminants.

As mentioned heretofore and as will be explained in greater detail later, theheavy gas oil withdrawn through line 6 is preferably subjected to a pretreatment in pretreating zone 8 and .then passed through line 9 into treating zone 10. The residual fraction, if it is relatively paranic, may be passed directly into the treating zone through line ll or, if aaphaltic, may be passed through line 12 to deasphalting zone 13 before being introduced into the treating zone through line 14.

Treating zone may comprise a series of absorber towers or other vessels adapted to permit the saturation of the oil with gaseous hydrogen chloride, hydrogen bromide, hydrogen iodide or hydrogen fluoride under the desired conditions of temperature and pressure. Suitable coils, iacketing or other heating means may be pro? vided. The gas is introduced into the treating zone through line 15 at a temperature preferably between about F., and about 300' F. and at a pressure which is preferably between about atmospheric and about 150 p.s.i.g. The contactvtime may range from a few minutes to several hours or more. Hydrogen halide gas is withdrawn from the treating zone through line 16 and may be passed toa receiver 11, from it my b9 con V slower.

tinuousl r cled to the treating zone. Make-up halide may be ZddeeccllI through line 18. The colloidally-dispersed nonvolatile contaminants present in thc oil are coagulated in the treating zone by the action of -the halide and the oil containing the coagulated contaminants is withdrawn therefrom through line 19.A Substantially no reaction between the halide and othcraconstituents of the oil takes place and therefore no sludge is formed in the oil.

The oil containing coagulated contaminants flows from the treating zone to separation zone 20 where the coagulated contaminants are collected and removed through line 21 andthe oil free of coagulated contaminants is withdrawn through line 22. Any of a number of wellknown separation methods, such as settling, filtration or centrifugation, may be employed for separating the oil and the coagulated metal compounds. Because of the high viscosity of the heavy gas oil and residua treated in the process, settling or centrifugation is normally preferred over filtration, which is considerably The decontaminated oil is introduced into stripping zonev 23 for the stripping o of dissolved halide gas. The stripping operation is preferably a two stage one wherein. an inert gas such as methane, carbondioxido or the like is employed to strip off the major part of the dissolved halide and then ammonia is used as a nal stripping gas. The ammonia readily reacts with any traces of the halide to form ammonium halide salts which because of their high water solubility, can be easily removed in the subsequent washing step of the process. The ammonia is also beneficial in that any residual ammonia tends-to reduce sulfur corrosion by forming salts with sulfur dioxide produced upon the burning of the oil. The volume of stripping gas employed will depend upon the amount of halide in the oil, which in turn depends upon the treating conditions employed. The stripping gas isintroduced into stripping zone 23 through line 24 and withdrawn overhead through line 25. The stripped oil is taken otf through line 26.

washing of the decontaminated oilis carried out in washing zone 21. The washing liquid may be introduced through line 28 and withdrawn through line 29. The oil substantially reduced in metallic contaminants is recovered through line 30. 'Ihe wash liquid may consist of caustic and water or instead may be an aqueous solution of magnesium sulfate. The use of magnesium sulfate has several advantages over caustic washing. The

introduction of sodium into the oil is undesirable because of ash formation, whereas the presence of small amounts of magnesium is benecial in that the magnesium in the oil whenv it is burned tends to combine with any residual vanadium present and thereby reduce ash corrosion. Saturated aqueous magnesium sulfate is particularly preferred as a .wash liquid because it has a high specific gravity and can thus be rapidly removed from the oil. The use of concentrated caustic in place of the conventional dilute caustic in order to achieve the same difference in specific gravity is less satisfactory because of the increased tendency of concentrated caustic to form emulsions. The volume of wash liquid used may be varied widely but will normally range between about 1 and 3 volumes per volume of oil.

The process thus described accomplishes the removal of colloidally dispersed nonvolatile contaminants from heavy gas oils and from nonasphaltic residua. In order to further demonstrate this process, reference will be made to exemplary data illustrating the process and the advantages achieved thereby.

In a rst series of experiments, samples were taken of three dierent representative residual petroleum fractions. The nickel and vanadium contents of these fractions were determined using chemical colorimetric methods, emission spectrographic methods and X-ray uorcscence methods. The samples were then ,treated in a glass-lined bomb with hydrogen hlgride gas at a pressureof from to 120 p.s.i. and a temperature of 250 F. for a period of 4 hours. The samples were then decanted to separate the oil from the coagulated metallic contaminants and the metals contents were again determined. The results obtained in these experiments are summarized in Table I below.

l Treated with HCI gas at 80 p.s.i.g. i Treated with HC1 gas at 120 p.s..g.

From the foregoing it can be seen that the treatment with HCl gas in accordance with the method of the 1nvention results in the coagulation of a substantial portion of the metallic contaminants present in the oil. These data are even more significant when it is considered that treated. Heat soaking at about 600 to 700 F. for about 3 to 12 hours has been found to result in the conversion of substantially all of the volatile contaminants in most high boiling fractions without the formation of large quantities of coke and gas due to thermal cracking. Such conditions are particularly preferred.

The heat soaking may be carried out by maintaining the oil in a closed, agitated vessel or may instead be carried out by passing the oil through a suitable bank of heaters or furnaces. The pressure during heat soaking is preferably maintained between about p.s.. and about 200 p.s.., although considerably higher pressures up to about 3000 p.s.. may be found advantageous under certain conditions.

The effect of heat soaking upon the coagulation of metallic contaminants can be seen by considering experiments carried out with a heavy atmospheric residuum. Upon treatment of this fraction with gaseous HCl at 225 F. and 80 p.s..g. for periods ranging from 20 hours to 140 hours, it was found that substantially no metals coagulation took place. Samples of the same fraction were then heat soaked as described above and treated with gaseous HC1 under the same conditions. It was found that from about 72 to 88% of the nickel and from about 62 to 73% of the vanadium present was coagulated and could be removed by filtration. These data are tabulated below.

the metals contents as reported above include the volatile contaminants which are not subject to coagulation in the absence of a pretreatment to convert them to anonvolatile form. Taking these volatile contaminants into account, the data indicate that an even hivher percentage of the nonvolatile contaminants were removed. In the case of residuum A, for example, 25% of the total nickel and 5% of the total vanadium were of the volatile type and therefore the treatment actually removed 75% of the nickel and 79% of the vanadium which could theoretically be coagulated.

As pointed out heretofore, treatment with hydrogen halides in accordance with the method of the present invention is effective for the removal of colloidally dispersed, nonvolatile metallic contaminants from petroleum gas oils and residua but has little effect upon the volatile type contaminants which are believed to be in true solution in the oil. It is therefore a particular feature of the present invention to subject the fraction to be freed of metallic contaminants to a suitable pretreatment in order to convert the volatile compounds to a nonvolatile form and thus permit their coagulation by treatment with a gaseous hydrogen halide. It has been found that these volatile type contaminants may be readily converted to the nonvolatile form by heat soaking the oil so that the monomeric porphyrins polymerize. The heat soaking is preferably carried out at temperatures between about 300 F. and about 750 F. in order to avoid cracking of the oil but higher temperatures may be utilized. The yield of treated oil will, of course, be decreased if substantial cracking occurs. The heat soaking may be continued over a period ranging from a few minutes to about 72 hours, depending upon the temperature conditions employed and the particular properties of the fraction The above data show that the heat soaking changed the character of the oil so that the metallic contaminants therein became susceptible to coagulation by gaseous HCl. It is believed that this was primarily due to the conversion of volatile contaminants to the nonvolatile form but some improvement probably occurred as a. result of the effect of the heat soaking upon the solutizing action of the asphaltenes present in the oil. Such a preliminary heat soaking may be applied to any gas oil, residuum or crude containing substantial quantities of volatile contaminants which is to be later subjected to treatment with a gaseous hydrogen halide.

As mentioned earlier, the asphaltenes present in asphaltic petroleum fractions exert a solutizing effect upon nonvolatile colloidally dispersed metallic contaminants and tend to prevent their coagulation by gaseous hydrogen halides. A mild hydrotreating reaction may be employed as a pretreatment for crude oils in the process of the present invention in order to overcome this solutizing effect and also to convert some of the volatile contaminants present in the oil to the nonvolatile form. Hydrotreating is a well-known operation in the petroleum processing art and there are numerous hydrotreating processes which are suitable for use in conjunction with this invention. All of these processes are similar and differ only slightly in the operating conditions and equipment employed. In a typical hydrotreating process the oil is preheated to a temperature in the range of from about 500 to about 900 F. and then introduced with excess hydrogen into a reactor containing a hydrogenation catalyst such as molybdena or cobalt molybdate on an alurnna carrier. The pressure in the reactor is preferably maintained between about 200 and about 800 p.s..g. Feed rates of from about 1 to 5 volumes per hour per volume of catalyst may be employed and from about 1000 to about 15,000 s.c.f. of hydrogen may be employed per barrel of feed. A regenerative system adapted to permit periodic regeneration of the catalyst by burning in air or other oxygen-containing gas may be employed but it is preferred to maintain the reactor conditions at a suticiently low level that no deposits are laid down on the catalyst. This level will vary somewhat depending upon the feed stock and may readily be established. The hydrotreated oil is withdrawn from the reactor, cooled and passed to a gas separation zone wherein the hydrogencontaining gases are recovered and recycled to the reactor for use. The oil may be stripped to remove hydrogen sulfide contained therein and then treated with a hydrogen halide in accordance with the invention.

The use of hydrotreating as a method for overcoming the metal solutizing effect of asphaltenes preparatory to treating with hydrogen halide gas in accordance with the invention is advantageous in that such hydrotreating simultaneously reduces the sulfur content of the oil and improves the oil stability, both of which are highly important in catalytic cracking feed stocks and residual fuels. Prior hydrotreating significantly increases the yield of gasoline obtained during subsequent catalytic cracking and decreases the production of coke and gases. Cracked products from such hydrotreated stocks are lower in sulfur, have higher octane numbers and require less treating than do similar cracked products from a virgin feed stock. The use of hydrotreating is thus preferred as, a preliminary treatment prior to metals removal where the dernetallized oil is to be used as a catalytic cracking feed stock.

The effect of hydrotreating upon metals coagulation is shown in Table III below. An asphaltic crude oil containing 65 p.p.m. of nickel, 496 p.p.m. of vanadium and 2.67 p.p.m. of sulfur was hydrotreated over a catalyst consisting of 13% cobalt molybdate on alumina. The oil was then treated with gaseous hydrogen chloride at a temperature of 225 F. and a pressure of 80 p.s.i.g. The metals contents of the untreated oil, the hydrotreated oil and the hydrotreated, HCl treated oil are compared below for two separate runs. Y

Table III EFFECT F HYDROTREATING oN METALS CoAGULATIoN Stock Ni.

p.p.m. p.p.m. p.p.'m.

496 nil 2. 67 nil eed Percent removal by HC1 Fun A Hydrogenated Product (12,3S0 s.c.f.) Hzlb.,

3.2 w./Hr./W. S30 p.s.l.g. 755 F Percent Removal HC1 Gas treated Hydrorenated Product- 74% Yield Perfeut Removal by HCL.-- Total Removal Hydrogenated Product (14,350 scf.) Halb.,

2.76 w./Hr./W. 830 psig., 750 F Percent Removal Percent Removal by HC1 Total Removal cracking feed stock or as a high grade residual fuel. This removal was largely due to the deposition of metals upon the hydrotreating catalyst. It is preferred to avoid this and thus considerably decrease the frequency with which the catalyst must be regenerated by employing only very mild hydrotreating. Suitable conditions for such a mild reaction are, for example, a temperature of from 500 to 700l F., a pressure of from about 200 to 400 p.s.i.g. a hydrogen rate of about 1000 to about 4000 s.c.f. per barrel, and a feed rate of from about 3 to about 5 volumes per hour per volume of catalyst.

As pointed out heretofore, the asphaltenes present in asphaltic residua exert a solutizing etect upon colloidally dispersed metallic contaminants and tend to prevent their coagulation by treatment with a gaseous hydrogen halide. This solutizing effect may also be overcome by the deasphalting of the oil. Any of a number of well-known deasphalting processes may be utilized. A preferred method involves the counter current contacting of the oil with a light hydrocarbon solvent such as propane, butane or the like in the presence of a higher boiling, aromatic wash oil such as the.heavy bottoms fraction from a catalytic cracking fractionator. The residuum and the wash oil are introduced into the upper portion of a deasphalting tower and ow downwardly countercurrent to a rising stream of solvent which is introduced into the lower portion of the tower. About 20 volume percent of the wash oil, based upon the residuum feed, is normally used. The oily constituents of the residuum are dissolved in the solvent and carried overhead from the tower through a heat exchanger to a stripping tower where the solvent is iiashcd off. The deasphalted oil remaining is cooled and may then be treated for the coagulation of metals.

The bottoms stream from the deasphalting tower consists essentially of wash oil, asphaltenes and small quantities of solvent. This fraction is heated and the solvent is ashed oi in a stripper. The wash oil containing asphaltenes recovered from the bottom of the tower may contain a considerable fraction of the metals originally in the feed, depending upon the deasphalted oil yields chosen. This material may be employed as asphalt in the conventional manner.

A particularly preferred method for deasphalting heavy residua containing metallic contaminants involves the injection of a gaseous hydrogen halide into the deasphalting tower with the deasphalting solvent. This procedure results in the major part of the metallic contaminants being carried into the bottoms fraction with the asphaltenes and permits much higher yields of deasphalted oil than can otherwise be obtained. It also obviates the necessity for separating coagulated metals from the oil. The presence of the metals in the asphalt will ordinarily not be objectionable. The effect of thus deasphalting and treating to coagulate metals at the same time is illustrated by the data set forth in -Table IV. Two highly asphaltic atmospheric residua were employed in the tests covered by the data. Neither residuum before deasphalting was susceptible to metals coagulation by treatment with gaseous HC1. Samples of each oil were deasphalted using pentane and pentene in combination with gaseous HCl and the metals contents were determined. It was found that the presence of the HCl resulted in considerably more of the contaminants being carried into the asphaltene fraction without any appreciable increase in yield loss. A sample of one of the oils was also heat soaked for 4 hours at 700 F. prior to deasphalting in the presence of gaseous HC1 and an even more significant reduction in metals was obtained.

HC1 contacting of theoil-pentane mixtures was cam'ed out by bubbling the gas at atmospheric pressure and subroom temperatures through the chilled mixture. The effectiveness of HC1 at these mild conditions confirms that the phenomenon occurring is a physical coagulation of colloids rather than a chemical reaction, i.e. acid treating. 0f course, when a heavy oil is to be treated 9 in the absence of solvent, viscosity considerations dictate the use of more severe HCl contacting conditions, such as 100 p.s.i.g. and 200 F. for example.

Table I V In order to minimize the yield losses incurred in deasphalting and demetallizing heavy residua, the asphaltencs containing metallic contaminants may be recombined with the deasphalted oil prior to treatment with a hydrogen halide gas for the coagulation of the metals. It has been found that the solutizing etect of the asphaltenes is in some way irreversibly destroyed during the deasphalting step and is-no longer in evidence when the oil and asphaltenes are recombined. Such recombining materially reduces the yield losses which are otherwise incurred and the metals removal upon subsequent treatment of the oil with hydrogen halide may be as good as that obtained by treating the desaphalted oil separately and discarding the asphaltenes.

The wash oil used to decrease the viscosity of heavy residua during deasphalting may be a heavy gas oil containing an appreciable concentration of metallic contaminants. The contaminants in both the gas oil and the residuum will be coagulated upon treating with hydrogen halide gas following the deasphalting step if the asphaltenes and deasphalted oil are recombined and thus the use of a valuable metals free fraction as a Wash oil may be avoided. The gas oil may, of course, be subjected to suitable pretreatment such as heat soaking or hydrotreating prior to being employed as a wash oil.

It will be understood that many modifications may be made in the process described above without departing from the scope of the invention. The pretreatment, if any, employed in conjunction with treatment for the coagulation of metals will depend upon the character of the oil and various combinations of heat soaking hydrotreating, deasphalting and treatment with hydrogen halide gas may be utilized. Such combinations and other modifications will be readily apparent to those skilled in the art.

What is claimed is:

1. A process for upgrading a hydrocarbon oil including constituents boiling in excess of about 950 F. which comprises in combination the steps of pretreating said oil at a temperature in the range of about 300 F. to about 900 F. for the conversion of volatile metallic contaminants therein to a nonvolatile form, coagulating nonvolatile metallic contaminants in said oil by contacting the oil with a hydrogen halide gas at a temperature in the range between about 30l F. and about 300 F., separating said oil and said coagulated contaminants, and recovering a treated oil of reduced metals content.

2. A process as defined by claim 1 wherein said pretreating step comprises contacting said oil with excess hydrogen at a temperature between about 500 F. and

l0 about 900 F. and at a pressure between about 200 and' about 800 p.s.i.g.

3. A process as defined by claim 1 wherein said pretreating step comprises heat soaking said oil at a temperature between about 300 F. and about 750 F.

4. A process for removing iron, nickel and vanadium porphyrins from a hydrocarbon oil and including constituents boiling in excess of about 950 F. which cornprises in combination the steps of heat soaking said oil at a temperature in the range between about 300 F. and about 750 F. to convert volatile porphyrins to a nouvolatile form, coagulating nonvolatile porphyrins in said oil by contacting the oil with a hydrogen halide gas at a temperature in the range between about 30 F. and about 300' F., separating coagulated porphyrins from said oil, and recovering a treated oil of reduced metals content.

5. A process as defined by claim 4 wherein said hydrogen halide gas is hydrogen chloride.

6. A process as defined by claim 4 wherein said oil is heat soaked for a period of from about 3 to about 12 hours.

7. A process as defined by claim 4 wherein said oil is heat soaked at a pressure between about 50 p.s.i. and about 200 p.s..

8. A process for removing iron, nickel and vanadium porphyrins from a hydrocarbon oil including constituents boiling in excess of about 950 F. which comprises in combination the steps of hydrotreatng said oil at a temperature of about 500 F. to about 900 F. and a pressure of about 200 to about 800 p.s.i.g. to convert volatile porphyrins to a nonvolatile form, coagulating nonvolatile porphyrins in said oil by contacting the oil with a hydrogen halide gas at a temperature in the range between about 30 F. and about 300 F., separating coagulated porphyrins from said oil, and recovering a treated oil of reduced metals content.

9. A process as defined by claim 8 wherein said hydrogen halide gas is hydrogen chloride.

l0. A process -as defined by claim 8` wherein said hydrotreating step is carried out at a temperature between about 500 F. and about 700 F., at a pressure between about 200 and about 400 p.s.i.g., and with a hydrogen feed rate of from about 1000 to about 4000 s.c.f. per barrel of oil.

11. A process for the selective removal of metallic contaminants from an asphaltic petroleum oil which comprises segregating an asphaltic petroleum crude oil into two oil fractions, the rst oil fraction boiling in the range between about 950 F. and about 1300 F. and the second oil fraction comprising residual oil boiling above about 1300 F., pretreating said lirst oil fraction at a temperature in the range of about 300 F. to about 900 F. for a sufficient time to convert volatile metallic contaminants contained therein to a nonvolatile form, deasphalting said second oil fraction, contacting said lrst and second oil fractions with a hydrogen halide gas at a temperature in the range of from about 30 F. to about 300 F. to coagulate metallic contaminants present in said fractions and thereafter segregating said oil fractions from said coagulated metallic contaminants.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PROCESS FOR UPGRADING A HYDROCARBON OIL INCLUDING CONSTITUENTS BOILING IN EXCESS OF ABOUT 950*F. WHICH COMPRISES IN COMBINATION THE STEPS OF PRETREATING SAID OIL AT A TEMPERATURE IN THE RANGE OF ABOUT 300*F. TO ABOUT 900*F. FOR THE CONVERSION OF VOLATILE METALLIC CONTAMINANTS THEREIN TO A NONVOLATILE FORM, COAGULATING NONVOLATILE METALLIC CONTAMINANTS IN SAID OIL BY CONTACTING THE OIL WITH A HYDROGEN HALIDE GAS AT A TEMPERATURE IN THE RANGE BETWEEN ABOUT 30*F. AND ABOUT 300*F., SEPARATING SAID OIL AND SAID COAGULATED CONTAMINANTS, AND RECOVERING A TREATED OIL OF REDUCED METALS CONTENT.
 11. A PROCESS FOR THE SELECTIVE REMOVAL OF METALLIC CONTAMINANTS FROM AN ASPHALTIC PETROLEUM OIL WHICH COMPRISES SEGREGATING AN ASPHALTIC PETROLEUM CRUDE OIL INTO TWO OIL FRACTIONS, THE FIRST OIL FRACTION BOILING IN THE RANGE BETWEEN ABOUT 950*F. AND ABOUT 1300*F. AND THE SECOND OIL FRACTION COMPRISING RESIDUAL OIL BOILING ABOVE ABOUT 1300*F., PRETREATING SAID FIRST OIL FRACTION AT A TEMPERATURE IN THE RANGE OF ABOUT 300*F. TO ABOUT 900*F. FOR A SUFFICIENT TIME TO CONVERT VOLATILE METALLIC CONTAMINANTS CONTAINED THEREIN TO A NONVOLATILE FORM, DEASPHALTING SAID SECOND OIL FRACTION, CONTACTING SAID FIRST AND SECOND OIL FRACTIONS WITH A HYDROGEN HALIDE GAS AT A TEMPERATURE IN THE RANGE OF FROM ABOUT 30*F. TO ABOUT 300*F. TO COAGULATE METALLIC CONTAMINANTS PRESENT IN SAID FRACTIONS AND THEREAFTER SEGREGATING SAID OIL FRACTIONS FROM SAID COAGULATED METALLIC CONTAMINANTS. 